Add protocol-v20 semantic bootstrap and readiness result framing so
`pmacs --gpu FILE` opens the requested path before the GPU window becomes
ready. Keep target identity scoped to the authenticated frontend, preserve
legacy/no-target attach behavior, and publish fresh buffers coherently to
existing replicas.
Carry Unix path bytes and launcher cwd through the root broker, resolve paths
lexically in the daemon, reuse or create buffers without ambient-view state,
and preserve the managed daemon lifecycle from #141. Add focused parser,
wire, lifecycle, hook, isolation, and real-connector acceptance coverage.